Core unit with collapsible pin for sand mold



April 10, 1962 R. E. WEDLAKE CORE UNIT WITH COLLAPSIBLE PIN FOR SAND MOLD 2 Sheets-Sheet 1 Filed NOV. 15, 1960 INVENTOR. .20) E. WEDLAKE.

April 10, 196 R. E. WEDLAKE CORE UNIT WITH COLLAPSIBLE PIN FOR SAND MOLD 2 Sheets-Sheet 2 Filed Nov. 15, 1960 Pig. 6

BY 61mm; W JZAA LQMM United States Patent 3,028,643 CORE UNIT WITH COLLAPSIBLE PIN FOR SAND MOLD Roy E. Wedlake, 20 Lincoln Ave., Wheatland, Pa., assignor of one-half to Martin E. Cusick, Sharpsville, Pa. Filed Nov. 15, 1960, Ser. No. 69,448 4 Claims. (Cl. 22-165) This invention relates to metal molding apparatus, and more particularly to a core unit used in a sand mold for hollow castings.

In my Patent 2,565,829, apparatus is shown for casting ingot molds. The core unit 10 includes a core pin 12 by which the core unit can be carried. In an attempt to prevent damage to the pin during extraction of the casting, the pin was made removable. However, the idea did not work out in practice as well as was expected.

It is among the objects of this invention to provide a core unit, in which during the casting operation the core pin will automatically move into a position where it will not be damaged during extraction, in which the molten metal that is poured into the mold causes the pin to move into a safe position, and in which the pin cannot become separated from the core.

In accordance with this invention a hollow upright core, sometimes called a core bar, has a central vertical opening through its upper end. Slidably mounted in this opening is a pin that has an enlarged lower end inside the core for supporting the core when the pin is lifted. The pin is provided with a transverse passage for receiving a dowel supported at its ends by the core bar when the pin is in elevated position. The dowel is consumable by the heat of molten metal poured around the core unit, whereupon the pin will drop down into the core. The inside of the core is provided with means for limiting the descent of the pin so that it can be raised later for carrying the core.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. 1 is a side view, partly in vertical section, of my core unit inside a flask;

FIG. 2 is an enlarged horizontal section taken on the line IIII of FIG. 1;

FIG. 3 is an enlarged fragmentary perspective view of the upper end of the core without the core pin;

FIG. 4 is a view similar to FIG. 1, showing extracting apparatus in place;

FIG. 5 is a side view of the core unit suspended from a crane or the like;

FIG. 6 is a fragmentary vertical section of the flask showing metal being poured into it; and

FIG. 7 is a fragmentary vertical section similar to FIG. 4, but showing the flask being stripped from the casting.

Referring to the drawings, an open bottom flask 1 rests on a base plate 2 and contains a core unit 3 that is spaced from the inner surface of the flask. That surface and the outside of the core unit are covered with molding sand 4. The particular apparatus illustrated is for casting ingot molds, but the principle of this invention also is applicable to molding apparatus for other hollow castings.

The core unit includes an upwardly tapered hollow metal core 6 that extends nearly to the top of the flask. The upper end wall of the core is provided with a central vertical opening 7, in which a core pin 8 is slidably mounted. The pin has an enlarged lower end or head 9 inside of the core for engagement with the upper wall so that the core can be lifted by the pin and carried about. The upper end of the pin is provided with 3,028,643 Patented Apr. 10, 1962 ICC a transverse passage 10, in which a horizontal rod 11 (FIG. 5) may be inserted for connection to a crane or the like to permit the core unit to be lowered into flask 1.

The core pin also is provided with a transverse passage 12 which, when the pin is in its upper position as shown in FIGS. 1, 5 and 6 is exposed at the top of the core. A dowel 13 extends through this passage and its projecting ends rest on the core bar to hold the pin up. The upper end of the core is provided with a shallow vertical socket 14 for receiving the lower end of a metal collar 15 that extends upward around the pin to a point directly below its upper passage 10. The collar is spaced from the pin. To prevent the dowel from interfering with seating of the collar in the socket, the side wall of the socket is provided with a pair of diametrically opposite notches 16 that receive the opposite ends of the dowel. Also, the bottom of the socket is provided with notches 17 in line with notches 16 so that the dowel will not project above the lower surface of the socket.

After this core unit has been placed in position in a flask and molding sand has been packed around it, molten metal 18 is poured into the flask around the core as shown in FIG. 6. The poured metal causes the dowel to disappear because it is consumed by the heat. Althrough the dowel can be made of low melting point metal, it is preferred to make it of combustible material, such as wood. As soon as the dowel has melted or burned away, the core pin will drop down into the core as shown in FIG. 4. To prevent the pin from falling to the bottom of the core, means is provided for stopping it with its upper passage 10 accessible through notches 16 so that a lifting rod can be inserted later. The pin arresting and supporting means may be merely a rod 19 extending across the inside of the core and mounted in its side walls.

After the poured metal has cooled sufl'lciently, collar 15 is removed from the top of the core as shown in FIG. 4 and then suitable extracting apparatus is pressed down on the core while simultaneously pulling upward on the flask to strip the flask from the casting, as shown in FIG. 7. The extracting apparatus includes an extractor pin 21 that has a recessed lower end which fits over the upper end of the core pin and presses down on the bottom of core socket 14. Due to the short projecting portion of the lowered core pin, there is no danger of bending or otherwise damaging it during the extracting operation.

After the core unit has been freed from the casting, the core pin 8 is raised in core 6 and a new dowel 13 is inserted in passage 12 to support the pin. The side of the pin is provided with a vertical spline 25 that slides in a slot 26 in the side of core opening 7 to prevent the pin from rotating in the core and swinging passages 10 and 12 out of alignment with notches 16 when a dowel is not in place. It will be seen that at no time can the pin become separated from the core. The descent of the pin into the core" during casting is entirely automatic.

According to the provisions of the patent statutes, I have explained the principle of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

1. A core unit for a sand mold, comprising a hollow upright core having a central vertical opening through its upper end, a carrying pin slidably mounted in said opening and having an enlarged lower end inside the core for supporting the core when the pin is lifted, the pin being provided with a transverse passage for receiving a supporting dowel having projecting ends supported by the core when the pin is in elevated position, said ends of the dowel being consumable by the heat of molten metal poured around the core unit, and means inside the core limiting the distance the pin can drop down into it when the dowelends'are consumed.

'2. A core unit as recited in claim 1, in'which said dowel is combustible.

3. A core unit for a sand mold, comprising'a hollow V upright core having a central vertical opening through its upper end, a carrying pin slidably mounted in said opening and having an enlarged lower end inside the core for supporting the core when the pin is lifted, the pin being provided with a transverse passage for receiving a supporting dowel when the pin is in elevated position, the upper end of the core having vertical notches for receiving the projecting ends of the dowel to support it, said ends of the dowel being consumable by the heat of molten metal poured around the core unit, and means inside the core limiting the distance the pin can drop down into it when the dowel ends are consumed.

4. A core unit for a sand mold, comprising a hollow .4 upright core having a vertical opening through its upper end encircled by a downwardly extending socket adapted to support a collar, 21 carrying pin slidably mounted in said opening and having an enlarged lower end inside the core for supporting the core when the pin is lifted, the pin being provided with a transverse passage for receiving a supporting dowl when the pin is in elevated position, the side wall and base of said socket having verticalnotches for receiving the projecting ends of the dowel to support it, said ends of the dowel being consumable by the heat of molten metal poured around the core unit, means inside the core limiting the distance the pin can drop down into-it when the dowel ends are consumed, and means holding the'pin against rotation in the core.

References Cited in the file of this patent UNITED STATES PATENTS 493,047 Simpson Mar. 7, 1893 665,865 Baker Jan. 15, 1901 922,678 Dimmick May 28, 1909 1,664,452 Daniels et al. Apr, 3, 1928 1,852,502 Brown -4 Apr. 5, 1932 2,565,829 Wedlake Aug. 28, 1951 

